Developing and evaluating techniques for localizing pollutant emission sources with open-path Fourier transform infrared measurements and wind data.
This paper presents the simulation and field evaluation results of two approaches to localize pollutant emission sources with open-path Fourier transform infrared (OP-FTIR) spectroscopy. The first approach combined the plume's peak location information reconstructed from the Smooth Basis Function Minimization (SBFM) algorithm and the wind direction data to calculate source projection lines. In the second approach, the plume's peak location was determined with the Monte Carlo methodology by randomly sampling within the beam segment having the largest path-integrated concentration. We first conducted a series of simulation studies to investigate the sensitivity of using different basis functions in the SBFM algorithm. It was found that fitting with the beta and Weibull basis functions generally gave better estimates of the peak locations than with the normal basis function when the plumes were mainly within the OP-FTIR's monitoring line. However, for plumes that were symmetric to the peak position or spread over the OP-FTIR, fitting with the normal basis function gave better performance. In the field experiment, two tracer gases were released simultaneously from two locations and the OP-FTIR collected data downwind from the sources with a maximum beam path length of 97 m. For the first approach, the release locations were within the 0.25- to 0.5-probability area only after the uncertainty of the peak locations was included in the calculation process. The second approach was easy to implement and still performed as satisfactorily as the first approach. The distances from the sources to the best-fit lines (i.e., the regression lines) of the estimated locations were smaller than 10 m.
Wu
Chang-Fu
CF
Department of Public Health and Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei, Taiwan, Republic of China. changfu@ntu.edu.tw
Chen
Ching-Hui
CH
Chang
Shih-Ying
SY
Chang
Pao-Erh
PE
Shie
Ruei-Hou
RH
Sung
Lung-Yu
LY
Yang
Jen-Chih
JC
Su
Jen-Wei
JW
D000395:Air Pollutants, Occupational / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis / Q000517:prevention & control*; D000465:Algorithms; D003198:Computer Simulation; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D014919:Wind
D000395:Air Pollutants, Occupational